clutch MAZDA MIATA 1991 Factory Service Manual

CARRIER PINION THRUST WASHER SPECIFICATIONS
Fig. 10: Measuring Carrier Gear Backlash

Courtesy of MAZDA MOTORS CORP.
LIMITED SLIP DIFFERENTIAL (RX7)
1. Check friction plate, disc and thrust washer thicknesses. See RX7 DIFFERENTIAL
SPECIFICATIONS . Measure and record thickness of 6 plate springs.
2. Measure thickness of complete clutch pack excluding conical springs. See Fig. 9
. Subtract conical spring
thickness and complete clutch pack thickness from 3.583" (91.00 mm). Difference should be .004-
010" (.10-.25 mm).
3. If clearance is excessive, use oversize friction discs. Oversize friction disc thickness is .0827" (2.10 mm).
Measure thickness of side gears, pressure rings, spider, pinion gears and thrust washers in place. See Fig.
9 .
Identifying MarkThickness In. (mm)
0.0787 (2.00)
05.0807 (2.05)
1.0827 (2.10)
15.0846 (2.15)
2.0866 (2.20)

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
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SWITCHES
SWITCHES LOCATION
MISCELLANEOUS
MISCELLANEOUS LOCATION
COMPONENT LOCATION GRAPHICS
ComponentLocation
Idle Speed Control SolenoidOn throttle body.
Purge Control Solenoid ValveOn right side of engine compartment, on shock
tower.
ComponentLocation
A/C Pressure SwitchOn high pressure refrigerant line.
Back-Up Light SwitchOn left side of transmission.
Clutch SwitchOn bracket, above clutch pedal. See Fig. 2 .
Neutral SwitchOn right rear side of transmission. See Fig. 2 .
Parking Brake SwitchOn base of parking brake lever.
Power Steering Pressure SwitchOn power steering housing assembly. See Fig. 2 .
Seat Belt Buckle SwitchOn driver's side seat belt buckle.
Stoplight SwitchOn bracket, above brake pedal. See Fig. 2 .
ComponentLocation
Diagnostic Check ConnectorOn left rear of engine compartment, near master cylinder. See Fig. 2 .
IgniterOn right rear corner of engine compartment, near fuse/relay block. See
Fig. 2
.
SRS Back-Up BatteryMounted below SRS control unit. See Fig. 3 .
NOTE: Figures may show multiple component locations. Refer to appropriate table for
proper figure references.

1991 Mazda MX-5 Miata
ELECTRICAL COMPONENT LOCATOR 1991 MAZDA ELECTRICAL COMPONENTS
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Blower motor relay supplies power to blower motor. Blower resistor determines blower speed. With blower
switch in highest position, blower motor is grounded through blower switch. With blower switch in all other
positions, blower motor is grounded through blower resistor and blower switch.
Circuit through compressor clutch is completed when A/C relay is energized and pressure switch is closed. A/C
relay is energized when Engine Control Unit (ECU) unit grounds the solenoid circuit of the relay. The ECU
energizes A/C relay if evaporator thermoswitch is closed and A/C and blower switches are on. The ECU also
controls A/C relay operation according to engine load.
ADJUSTMENTS
AIRFLOW MODE DOOR
Set airflow mode control lever to vent position. Disconnect control cable at airflow mode door lever. Extend
airflow mode door lever until it stops, and hold it there. See Fig. 1
. Attach control cable to door lever and clip.
Ensure control lever moves freely between defrost and vent positions.
AIR-MIX (TEMPERATURE BLEND) DOOR
Set temperature control lever to maximum hot position. Disconnect control cable at air-mix door lever. See Fig.
1 . Extend air-mix door lever until it stops, and hold it there. Attach control cable to door lever and clip. Ensure
control lever moves freely between hot and cold positions.
RECIRCULATED/FRESH AIR DOOR
Set recirculated/fresh air control lever to fresh position. Disconnect control cable at recirculated/fresh air door
lever. Retract recirculated/fresh air door lever until it stops, and hold it there. Attach control cable to door lever
and clip. Ensure control lever moves freely between recirculated air and fresh air positions.
TESTING
AIR BAG WARNING
BLOWER MOTOR CIRCUIT
1. Check 30-amp HEATER circuit breaker in passenger compartment fuse panel. If Red button has not
popped out, go to next step. If Red button has popped out, repair short circuit and press Red button to
reset circuit breaker.
2. Turn ignition on. Turn blower switch to 4th position (high). Check voltage at Blue wire terminal of 2-
wire blower motor connector on bottom of blower case. If no voltage is present, repair wiring between
circuit breaker and blower motor. WARNING:To avoid injury from accidental air bag deployment, read and carefully
follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR
BAG SYSTEM procedures in AIR BAG article in the
ACCESSORIES/SAFETY EQUIPMENT Section.

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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3. If battery voltage is present, turn off blower switch and A/C switch (if equipped). Check voltage at
Blue/Red wire terminal of blower resistor 1-wire connector. If no voltage is present, replace blower
motor. If battery voltage is present, check voltage at Blue/White wire terminal of blower resistor
connector.
4. If no voltage is present, replace blower resistor. If battery voltage is present, check voltage at Blue/Red
wire terminal of blower resistor 4-wire connector. If no voltage is present, replace blower resistor.
5. If battery voltage is present, check voltage at Blue/Green wire terminal of blower resistor connector. If no
voltage is present, replace blower resistor. If battery voltage is present, check voltage at Blue/Yellow wire
terminal of blower resistor connector.
6. If no voltage is present, replace blower resistor. If battery voltage is present, turn ignition on and blower
switch to 4th position (high). Check voltage at Black wire terminal of blower switch connector. If battery
voltage is present, repair wiring between blower switch and ground.
7. If no voltage is present, turn ignition switch, blower switch and A/C switch off. Check voltage at
Blue/White wire terminal of blower switch connector. If no voltage is present, repair wiring between
blower resistor and blower switch.
8. If battery voltage is present, check voltage at Blue/Red wire terminal of blower switch connector. If no
voltage is present, repair wiring between blower resistor and blower switch. If battery voltage is present,
check voltage at Blue/Green wire terminal of blower switch connector.
9. If no voltage is present, repair wiring between blower resistor and blower switch. If battery voltage is
present, check voltage at Blue/Yellow wire terminal of blower switch connector. If battery voltage is
present, replace blower switch. If no voltage is present, repair wiring between blower resistor and blower
switch.
COMPRESSOR CLUTCH CIRCUIT
1. Turn ignition on. Check 20-amp WIPER fuse in passenger compartment fuse block. Check 20-amp AD
FAN (additional fan) fuse in engine compartment fuse block. If fuses are blown, repair short circuit.
2. If fuses are okay, run engine at idle. Turn A/C and blower switches on. Check voltage at compressor
clutch connector (Black/Red wire terminal). If no voltage is present, go to step 5).
3. If battery voltage is present, turn ignition off. Disconnect evaporator thermoswitch connector. Check
continuity between switch terminals. If there is no continuity, replace evaporator thermoswitch.
4. If there is continuity, disconnect compressor clutch connector. Set ohmmeter to X1000 scale. Check
continuity between compressor clutch connector and ground. If there is no continuity, replace compressor
clutch. If there is continuity, adjust compressor clutch air gap or check compressor for internal damage.
5. Run engine at idle. Turn A/C and blower switches on. Check voltage at Black/Blue wire terminal of A/C
relay connector. If battery voltage is present, go to step 9).
6. If no voltage is present, check voltage at Blue/Yellow wire terminal of A/C relay connector. If no voltage
is present, repair circuit between 20-amp AD FAN fuse and A/C relay.
7. If battery voltage is present, check voltage at Blue wire terminal of A/C relay connector. If no voltage is
present, repair circuit between 20-amp WIPER fuse and A/C rela
y. NOTE: Blower resistor uses a 1-wire connector and a 4-wire connector. The wire
in the 1-wire connector is Blue/Red, and one of the wires in the 4-wire
connector is Blue/Red. Check voltage at appropriate wire.

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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8. If battery voltage is present, check voltage at Blue/Black wire terminal of A/C relay connector. If no
voltage is present, replace A/C relay. If battery voltage is present, check Engine Control Unit (ECU)
terminal voltage.
9. Turn ignition off. Disconnect pressure switch connector. Check continuity between switch terminals. If
there is continuity, repair circuit between A/C relay and compressor clutch.
10. If there is no continuity, connect manifold pressure gauges to system. If low pressure is 21-43 psi (1.5-3.0
kg/cm
2 ) and high pressure is 171-235 psi (12.0-16.5 kg/cm2 ), replace pressure switch. If pressures are
not as specified, check refrigerant system for proper charge.
CONDENSER (ADDITIONAL) FAN CIRCUIT
1. Turn ignition on. Turn A/C and blower switches on. Check voltage at Black/Blue wire terminal of
condenser fan connector. If no voltage is present, repair circuit between A/C relay and condenser fan.
2. If battery voltage is present, check voltage at Black wire terminal of condenser fan connector. If no
voltage is present, replace condenser fan motor. If battery voltage is present, repair circuit between
condenser fan and ground.
A/C & BLOWER SWITCH
With switches in positions indicated, check continuity between specified terminals of A/C and blower switch
connector. See Fig. 1
. If continuity is not as specified, replace A/C and blower switch.

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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Disconnect electrical connectors from blower case. Remove glove box. Loosen seal plate between blower motor
case and evaporator case. Remove blower motor case nuts. Remove case and seal plate. To install, reverse
removal procedure.
COMPRESSOR
Removal & Installation
1. Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling
equipment. Disconnect compressor clutch connector. Disconnect refrigerant lines from compressor.
Remove drive belt.
2. Raise and support vehicle. Remove compressor mounting bolts and remove compressor. To install,
reverse removal procedure. Adjust drive belt to specified tension. Evacuate and charge system.
CONDENSER & RECEIVER-DRIER
Removal & Installation
Discharge A/C system using approved refrigerant recovery/recycling equipment. Raise and support vehicle.
Remove splash shield and air guide. Remove condenser and receiver-drier as an assembly. To install, reverse
removal procedure. Evacuate and charge system.
CONTROL PANEL
Removal & Installation
Remove rear console assembly. See Fig. 4 . Remove vent outlets from center panel assembly. Remove center
panel assembly. Remove control panel screws. Pull control panel from hole. Disconnect door control cables
from back of control panel and remove panel. To install, reverse removal procedure.
EVAPORATOR CORE & THERMOSWITCH
Removal & Installation
1. Discharge A/C system using approved refrigerant recovery/recycling equipment. Remove condenser and
receiver-drier as an assembly. Disconnect low-pressure and high-pressure pipes from evaporator tubes at
engine compartment firewall.
2. Remove right undercover and glove box. Disconnect thermoswitch electrical connector. Loosen left seal
plate (between heater case and evaporator case). Loosen right seal plate (between evaporator case and
blower motor case).
3. Remove evaporator case. Disassemble evaporator case, and remove evaporator core and thermoswitch.
See Fig. 3
. To install, reverse removal procedure. Evacuate and charge system.

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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STARTER - DIRECT DRIVE
1990-92 ELECTRICAL Mazda Starters - Direct Drive
DESCRIPTION
Nippondenso direct drive starter is a conventional 12-volt, 4-pole, brush-type starter. The integral solenoid is
attached to the drive housing. The overrunning clutch pinion drive is mounted directly on armature shaft drive
end.
TROUBLESHOOTING
TESTING (ON VEHICLE)
CIRCUIT TESTING
1. Turn ignition switch to START position, depress clutch and ensure starter operates. If starter does not
operate, use voltmeter to check voltage at "S" terminal when clutch is depressed and ignition is turned to
START position. See Fig. 1
.
2. If voltage is less than 8 volts, check starter interlock switch and ignition switch to starter wiring circuit for
short to ground. If voltage is greater than 8 volts and starter is inoperative, starter has an internal fault.
Repair or replace as required. NOTE: For information on B2200 and Protege models with automatic transmissions,
see STARTERS - GEAR REDUCTION article.
NOTE: See TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL
INFORMATION section.
NOTE: Before testing, ensure battery is fully charged, battery cables and terminals are
clean and tight and engine grounds are good.

1991 Mazda MX-5 Miata
STARTER - DIRECT DRIVE 1990-92 ELECTRICAL Mazda Starters - Direct Drive

1991 Mazda MX-5 Miata
STARTER - DIRECT DRIVE 1990-92 ELECTRICAL Mazda Starters - Direct Drive
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Fig. 1: Direct Drive Starter Circuit Diagrams
Courtesy of MAZDA MOTORS CORP.
STARTER INTERLOCK SWITCH (CLUTCH START SWITCH)
Switch is mounted on bracket near top front of clutch pedal. Disconnect switch harness connector. Using
ohmmeter, ensure continuity exists between switch connector terminals when clutch pedal is depressed. If

1991 Mazda MX-5 Miata
STARTER - DIRECT DRIVE 1990-92 ELECTRICAL Mazda Starters - Direct Drive
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SOLENOID PULL-IN TEST
Connect positive battery lead to solenoid "S" terminal and negative battery lead to solenoid case. Starter pinion
drive gear should extend quickly and maintain this position. If starter pinion drive gear does not extend, replace
solenoid. See Fig. 2
.
SOLENOID RETURN TEST
Connect positive battery lead to solenoid "M" terminal and ground negative battery lead to starter body. Using
screwdriver, pry overrunning clutch pinion drive outward. Release screwdriver and ensure overrunning clutch
pinion drive returns to original position. See Fig. 2 .
SOLENOID
1. Disconnect all wires to solenoid. Using ohmmeter, ensure continuity between "S" and "M" terminals, and
between "S" terminal and solenoid body. See Fig. 1
. If continuity does not exist between these terminals,
solenoid must be replaced.
2. Next ensure continuity does not exist between "M" and "B" terminals. If continuity exists between these
terminals, solenoid is shorted and must be replaced.
PINION GAP ADJUSTMENT
1. Ensure field wire is disconnected from solenoid "M" terminal. Connect positive battery lead to "S"
terminal and negative battery lead to starter case. Starter pinion drive gear will extend outward and stop.
2. Quickly measure pinion gap clearance between end of pinion drive and circlip retainer. See Fig. 3
. DO
NOT operate starter solenoid for more than 10 seconds. Pinion gap clearance should be .02-.08" (0.5-2.0
mm).
3. If pinion gap clearance is not within specification, adjust by increasing or decreasing thickness of
solenoid shims located between solenoid and drive housin
g. NOTE: Solenoid tests must be performed with starter assembled and field lead ("M"
terminal wire) disconnected at the solenoid.
CAUTION: Do not engage starter solenoid for more than 10 seconds during testing or
damage to coil winding may result.

1991 Mazda MX-5 Miata
STARTER - DIRECT DRIVE 1990-92 ELECTRICAL Mazda Starters - Direct Drive
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to field coil housing. If continuity exists, repair or replace field coil.
OVERRUNNING CLUTCH PINION DRIVE
Hold overrunning clutch housing and turn pinion gear by hand. If pinion turns in both directions, clutch is faulty
and must be replaced. DO NOT clean overrunning clutch with solvent, as it is packed with grease and sealed by
manufacturer.
REMOVAL & INSTALLATION
1. Disconnect negative battery cable. Raise vehicle on hoist. Remove undercover. Disconnect wiring from
starter. Remove differential lock assembly (4WD models). On Protege (M/T) and 323 models, remove
support brace from under intake manifold. Remove starter mounting bolts. Remove lowest mounting bolt
last. Remove starter from under side of vehicle.
2. To install starter, reverse removal procedure. Tighten mounting bolts to 23-24 ft. lbs. (31-46 N.m).
Tighten battery terminal nut to 87-104 INCH lbs. (9.8-12 N.m).
OVERHAUL
DISASSEMBLY & ASSEMBLY
1. Mark rear cover, field coil housing and front drive housing for reassembly reference. Remove solenoid
and shims, rear cover and brush plate. Remove field coil housing and pull armature and yoke lever from
front drive housing. See Fig. 4
& Fig. 5. Use arbor press to remove circlip, stopper and pinion drive from
armature shaft. See Fig. 6
.
2. To assemble, reverse removal procedures. Lubricate solenoid plunger, yoke lever and armature bushings.
Use arbor press and pinion drive to install stopper and circlip on armature shaft. See Fig. 6
. Ensure brush
plate, rear cover and field coil housin
g are aligned when installing through bolts.

1991 Mazda MX-5 Miata
STARTER - DIRECT DRIVE 1990-92 ELECTRICAL Mazda Starters - Direct Drive
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